Transport system for a mould-string casting plant

ABSTRACT

In a transport system for a mould-string casting plant comprising a moulding machine ( 1 ) delivering a plurality of uniform mould parts ( 3 ) to a string of moulds on the transport system transporting the moulds from the moulding machine ( 1 ) to a pouring station ( 4 ) and further on to a solidification and cooling section (II, III, IV) and ending at a knock-out station in which the castings are taken out of the moulds ( 3 ), the transport system comprises in combination—a second section (II), in which the moulds ( 3 ) in the string are transported slidingly by means of movable longitudinal side rails ( 8 ) applying a positive lateral force on each side of the mould string ( 3 ) and moving in an advancing and longitudinal stepwise manner synchronised with the movement provided by the pressure plate ( 2 ) of the moulding machine ( 1 ), and—a third section (III), in which the transport is effected by means of a walling beam system ( 6, 7 ). In this way it is possible to provide a longer high-precision transport than possible when only using either side rail transport or walking beam transport.

TECHNICAL FIELD

The present invention relates to a transport system for a mould-stringcasting plant of the kind set forth in the preamble of claim 1.

BACKGROUND ART

In transport systems for mould-string casting plants of this kind it isknown to effect the transport by means of the pressure plate expellingthe formed moulds from the moulding machine and supplementary mechanicalmeans in the form of movable longitudinal side rails applying a positivelateral force on each side of the mould string and moving in anadvancing and longitudinal stepwise manner synchronised with themovement provided by the pressing plate of the moulding machine, saidmechanical means being positioned close to the moulding machine forgripping the moulds immediately after leaving said moulding machine. Atransport system of this kind is known from U.S. Pat. No. 3,744,552.

Another supplementary mechanical means for providing the forwardmovement of the mould string comprises an array of equally spaced,parallel, rigid rails extending in the direction of the movement of themould string from the moulding machine. The array of equally spacedrails comprises fixed rails and movable rails, said movable rails beingmoved by mechanical and hydraulic means and positioned between the fixedrails in an alternate manner, the movable rails being moved in a cyclicmanner synchronised with the movement provided by the pressing plate ofthe moulding machine, said cyclic movement of the movable railscomprising lifting the movable rails to support the mould string, movingone step forward, lowering the movable rails leaving the mould stringsupported on the fixed rails, and moving the movable rails back to theirinitial position ready to be lifted again to support the mould string inorder to minimise the vertical movement of the moulds and reduce thefriction, the so-called fixed rails are lowered during the forwardmovement of the movable rails. A transport system of this kind is knownfrom DE-2,311,253.

It is furthermore known to provide a belt conveyor for performing thefinal transport of the mould string towards the knock-out station, saidbelt conveyor being positioned to receive the mould string aftersufficient solidification of the mouldings, whereby the precision of thetransport is less significant for obtaining precision mouldings.

In connection with modern moulding machines having a high productionrate, the distance over which the mould string has to be transportedbefore reaching the knock-out station increases and furthermore, thedistance over which the precision conveyance of the mould string isessential for obtaining precision mouldings by avoiding dislocation ofindividual mould parts relative to one another, is also increasing.Accordingly, there exists a demand for extending the high-precision partof the transport system as well as the total length of the transportsystem.

DISCLOSURE OF THE INVENTION

It is the object of the present invention to provide a transport systemfor a mould-string casting plant of the kind referred to above, withwhich it is possible to provide a longer high-precision transport partand a longer total length of the transport system, and this object isachieved with a transport system of said kind, which according to thepresent invention also comprises the features set forth in thecharacterising clause of claim 1. With this arrangement, thehigh-precision sliding transport of the mould string can be extendedrelatively long until problems arise in connection with the contactbetween the side rails for the sliding transport, whereupon a walkingbeam transport can take over the transport of the mould string, saidwalking beam transport also being of a relatively high-precision typeavoiding dislocation of mould parts relative to one another, and thewalking beam transport system extending as long as possible until apossible belt conveyor transport system can take over the transportafter sufficient solidification of the castings. The combination of thepressure plate transport, side rail transport and walking beam transportprovides the possibility of extending the high-precision transport to alonger distance than possible with the existing systems which only usepressure plate transport combined with either side rail or walking beamtransport.

Preferred embodiments of the invention, the advantages of which will beevident from the following detailed part of the present description, arerevealed in the subordinate claims.

Due to the fact that the supplementary mechanical movement means of thesecond section are not active in the start of the mould string, aspecial method for emptying the transport system may be implemented, asrevealed in the method claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed part of the present description, the inventionwill be explained in more detail with reference to the exemplaryembodiments of a transport system for a mould-string casting plantaccording to the invention shown in the drawings, in which

FIG. 1 shows a schematic side view in elevation of a preferredembodiment,

FIGS. 2 and 3 show a cross-section of a walking beam transport system indifferent movement phases, and

FIGS. 4 and 5 show a cross-sectional view and a side view of a side railmoving system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The transport system shown in FIG. 1 comprises the hydraulicallyoperated pressure plate 2, which stepwise advances the uniform castingmoulds 3 along the first section of the conveyor part I, which extendsfrom the moulding machine to just beyond the pouring section 4. Thesecond section of the transport system II covers the solidification andcooling sections. The third section of the transport system III takesover the transport in the cooling section and transfers the moulds withthe casting therein to a synchronised belt conveyor 11, likewise beingpart of the cooling section leading to the knock-out station, where thecastings are taken out of the moulds.

In the first part of a conveyor part I, the moulds are guided in achannel provided by means of a bottom and possibly two fixed side railsguiding the produced moulds during their sliding movement towards thepouring station.

The side rail transport system in the second transport section II shownin FIGS. 4 and 5 comprises longitudinal side rails 8 movable to engageand grip the moulds 3, whereupon the rails 8 are advanced one step,resulting in the gripped mould string advancing at same rate along thebase plate 9. The longitudinal side rails 8 are then released from themoulds in the mould string 3 and returned to the original position. Theforward and backward movements of the side rails 8 are performed bymeans of a piston 10 shown in FIG. 5, and the respective longitudinaland transverse movements of the side rails and the mould string aredenoted by arrows in FIGS. 4 and 5.

The side rail transport system may extend all the way from the mouldingmachine to the walking beam transport system but preferably only from aposition downstream of the pouring station 4, in which position thecastings have achieved a solidified outer shell.

The walking beam transport system of the third transport section IIIshown in FIGS. 2 and 3 provides a longitudinal stepwise movement of themoulds 3 as follows: The movable rails 6 are raised to support themoulds 3, as shown in FIG. 2, whereupon the movable rails 6 are moved inlongitudinal direction one step forward and lowered to the positionshown in FIG. 3, whereby the moulds 3 are supported on the fixed rails7. In this position, the movable rails 6 are moved back ready forraising again to support the moulds 3 and moving them one step furtherforward, said forward movement naturally being performed in synchronismwith the stepwise forward movement provided by the pressure plate 2 andthe side rail transport system II. In FIGS. 2 and 3, the verticalmovement of the movable rails 6 are highly exaggerated, the raising ofthe moulds 3 should be minimal in order to avoid dislocation of themoulds 3 relative to one another at the transition between the secondtransport section II and the third transport section III. In thisrespect it is also possible to lower the so-called fixed rails 7 tosecure the support on the movable rails 6 during the forward movement,and raising the fixed rails 7 again before lowering the movable rails 6.In this way, the vertical movement of the moulds 3 may be reduced toclose to zero.

The first transport section I provides a secure and stable contactpressure or weighting between the mould parts in the pouring station 4,and the friction between the moulds 3—positioned between the mouldingmachine 1 and the pouring station 4—and the sliding section issufficient to maintain this contact pressure even when the hydraulicallyoperated pressure plate 2 is moved back into the moulding machine 1 forproducing the next mould 3.

In order to be able to empty the system, when changing from one type ofcasting to another or any other production stop, lightweight dummyblocks can be inserted instead of new moulds, to enable all the castmoulds to reach the supplementary mechanical means for providing theforward movement thereof, and using the hydraulically operated pressureplate 2 to move said dummy blocks forward and thus provide the slidingmovement of the casting moulds 3 in the section I. Another way ofemptying the system would be to provide a separate set of longitudinalside rails 8 for the section I, which however would only be brought intoengagement with the casting moulds 3 during such emptying of thetransport system, in order to maintain the above advantage of providinga desired contact pressure between the mould parts in the mould stringduring normal operation. In order to maintain a suitable pressurebetween the mould parts during emptying, this side rail transport systemfor the section I should possibly be advanced further than thecorresponding transport system in the section II.

One further advantage of the system in accordance with the presentinvention should be mentioned, namely that at the pouring station 4, themould string 3 may be supported by a planar surface free from side railsor movable rails under the bottom, whereby possible failures of themoulds during pouring resulting in outrunning hot metal can easily becleaned up, at least compared to the big problems arising when suchoutrunning metal runs into the movable and stationary rails 6, 7, orinto the moving mechanism for the side rails 8 in a similar position.Furthermore, the free sides and planar bottom of the transport system insection I provide the possibility of pouring from the side or even fromthe bottom of the mould string, which is especially interesting inconnection with casting of light alloys.

In connection with moulding machines producing a high number of mouldsper hour, it is necessary to have a relatively long transport section inorder to cause a solidification and cooling of the castings before theknockout station. In this connection, it is interesting to have severaldifferent types of transport systems along the solidification andcooling sections, i.e. combining the first sliding transport section Iwith a side rail transport section II and possibly a synchronised beltconveyor 11, as shown in FIG. 1, and combinations of side rail transportsystems and walking beam systems at the bottom are provided, especiallywhen the casting moulds have a tendency of disintegrating due to thedrying out of the mould 3 during pouring, solidification and cooling ofthe castings, said drying out possibly causing malfunction of the siderail transport system, at which point the walking beam system takesover.

The invention has been described above in connection with preferredembodiments thereof and several modifications may be envisaged withinthe scope of the following claims.

1. Transport system in a mould-string casting plant comprising amoulding machine delivering a plurality of uniform mould parts to astring of moulds on the transport system transporting the moulds fromthe moulding machine to a pouring station and further on to asolidification and cooling section and ending at a knock-out station inwhich the castings are taken out of the moulds, characterized by saidtransport system comprising in combination a second section, in whichthe moulds in the string are transported slidingly by means of movablelongitudinal side rails applying a positive lateral force on each sideof the mould string and moving in an advancing and longitudinal stepwisemanner synchronized with the movement provided by the pressure plate ofthe moulding machine, and a third section, in which the transport iseffected by means of a walking beam system.
 2. Transport system inaccordance with claim 1, characterized by further comprising a firsttransport section, in which the moulds in the string are transportedslidingly, said sliding transport being provided by the pressure plateof the moulding machine expelling the moulds from the moulding machine.3. Transport system in accordance with claim 1, characterized by furthercomprising a fourth section following the third section, said fourthsection being provided in the form of a conveyor belt.
 4. Transportsystem in accordance with claim 2, characterized by said first sectionextending at least to a position corresponding to the pouring station.5. Transport system in accordance with claim 2, characterized by saidfirst section extending to a position downstream of the pouring station,in which position the castings have achieved a solidified outer shell.6. Transport system in accordance with claim 1, characterized by thesliding surface of the sections and consisting of planar surfaces or asingle planar surface.
 7. Transport system in accordance with claim 1,characterized by the sliding surfaces of sections and being divided intoa planar upstream surface and a downstream grille-like surface.